Glossary
Attenuation
The proportion of the wort’s extract that fermentation removed — how far the yeast got through the available sugar.
Also called attenuated.
The full record
Attenuation has its own catalogue entry with the detail this page summarises — causes, thresholds, related styles and evidence.
Attenuation — The proportion of wort sugars a yeast consumes — the single biggest determinant of how sweet or dry a finished beer tastes.
Attenuation is what separates a dry beer from a sweet one at the same starting gravity. A saison attenuating to 90% finishes bone dry; an English mild attenuating to 68% keeps a good deal of residual sweetness and body.
It depends on three things together: the yeast strain’s appetite, the fermentability of the wort as determined by mash temperature, and the health of the fermentation. A brewer chasing dryness manages all three rather than any one.
Related
- Apparent attenuation — The figure normally quoted, and why it overstates.
- Mash temperature — The main lever on how fermentable the wort is.
- Flocculation — Yeast dropping out early is a common cause of low attenuation.
More vocabulary
ABV · ABW · Alcohol unit · Alkalinity · Alpha acid · Apparent attenuation · Beta acid · Cohumulone · Degrees Lovibond · Degrees Plato
See every term on the glossary index.
Last reviewed 2026-08-16.